The Well-Grounded Rubyist, Second Edition

9.4. Ranges

A range is an object with a start point and an end point. The semantics of range operations involve two major concepts:

• Inclusion —Does a given value fall inside the range?
• Enumeration —The range is treated as a traversable collection of individual items.

The logic of inclusion applies to all ranges; you can always test for inclusion. The logic of enumeration kicks in only with certain ranges—namely, those that include a finite number of discrete, identifiable values. You can’t iterate over a range that lies between two floating-point numbers, because the range encompasses an infinite number of values. But you can iterate over a range between two integers.

We’ll save further analysis of range iteration and enumeration logic for ...